Yes of course its possible! Works splendid, a perfect controller for your emulator gaming or simply just your PC game! A guide for how to do this in windows can be found Here
But, this requires some "hacking", drivers and such, for it to work. The most remarkable thing i noticed, was that in a Linux based OS (I only tested ubuntu and arch) it worked "out of the box"! Meaning, no need for drivers or programs. Its just being treated as if it was a normal usb controller! Now how awesome aint that!
PS3, PS2, PS1, NES, N64, all of this and more, with your lovely PS3 Controller!
There are also possibilites of using the sixaxis function on a computer, but are more advanced. See for example this, well maybe not practical, but very cool!
